Biodegradable Nanocomposite of ZnS(Mn) Quantum Dots Immobilized Graphene Oxide for Bioimaging Applications

Abstract

Developing a biocompatible and biodegradable graphene-based fluorescent nanoprobe with the ability to visualize live cells could be interesting for intracellular imaging and monitoring the efficiency of chemotherapy. Herein, we report a biodegradable and biocompatible hybrid fluorescent graphene oxide (GO)-ZnS(Mn) composite synthesized via in situ growth of ZnS(Mn) quantum dots (QDs) on the surface of GO in the aqueous medium. The prepared 'GO-ZnS(Mn)' composite was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA) and high-resolution transmission electron microscopy (HR-TEM) along with selected area electron diffraction (SAED). Further, the fluorescence properties of the GO-ZnS(Mn) composite were studied using fluorescence emission spectroscopy. The composite material exhibited a strong and broad visible light fluorescence from 500 to 600 nm by excitation with 365 nm (UV) light. The cytotoxic experiments of folic acid (FA) conjugated GO-ZnS(Mn) using MTT [(3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide)] assay revealed that the composite had excellent biocompatibility even at higher concentrations up to 200 µg/mL in HeLa cell lines. Next, the bioimaging experiments carried out using confocal fluorescence laser scanning microscopy (CLSM) revealed that GO-ZnS(Mn) composite was taken up by the HeLa cells effectively within 12 h of incubation via receptor (folate) mediated endocytosis with strong fluorescence throughout the cell surface. Finally, the biodegradability of GO-ZnS(Mn) composite was studied by treating it with human myeloperoxidase enzyme (hMPO) isolated from the primary immune cells, neutrophils, which is important to understand the in vivo fate of GO-Zns(Mn). The HR-TEM and Raman analyses confirmed the biodegradation of GO-ZnS(Mn) within 15 h of hMPO treatment. Thus, the biodegradable GO-ZnS (Mn) composite could be helpful for chemotherapy and bioimaging applications.

Recent Advances in Two-Dimensional Nanomaterials for Healthcare Monitoring

“…It exhibited strong visible light fluorescence and excellent biocompatibility in HeLa cell lines, even at higher concentrations. Confocal fluorescence microscopy demonstrated effective cellular uptake via receptor-mediated endocytosis within 12 h. Biodegradability studies with human myeloperoxidase enzymes confirmed degradation within 15 h, indicating its potential for biomedical applications …”

“…Confocal fluorescence microscopy demonstrated effective cellular uptake via receptor-mediated endocytosis within 12 h. Biodegradability studies with human myeloperoxidase enzymes confirmed degradation within 15 h, indicating its potential for biomedical applications. 177 Hydrogels reinforced with oxidized few-layer graphene (GO) demonstrated slower degradation compared to hydrogels without GO in vivo studies. Despite the degradation process, no signs of inflammation or infection were observed at the implantation sites, indicating good biocompatibility.…”